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www.inbroadcast.com | Vol: 7 - Issue 4 | April 2017
InTech
Playback T&M And Quality Control cont'd...
NAB Developments
Beyond QC, Interra talks about offer
QA (quality assurance). The latest
version of its BATON solution enhances
AQC by allowing users to add manual
(eyeball) checks. With this hybrid
approach, operators can detect certain
issues, such as lip sync, which AQC
solutions cannot.
"While automation has been
transformative
for
the
broadcast
community
in terms of speeding up
workflows, AQC tools do
not fully implement an
organisation's
overall
QC policy," says Ashish
Basu, VP, Global Sales and
Business
Development,
Interra Systems. "Relying
on a combination of AQC and manual
intervention is ultimately the best
approach to understanding false
negatives and positives, detecting
critical issues that aren't yet detected
by automation alone, and taking
appropriate corrective measures."
The platform includes an enhanced
BATON Media Player that shows a list
of user-defined manual QC checks
enabled in the test plan, allowing users
to add necessary errors on the content
timeline, as well as review AQC results.
"The result is a well-integrated and
more efficient broadcast workflow,"
says Westlake.
New data analysis features unveiled
at NAB "allow users to effectively
track trends and anomalies in media
content, optimising decision-making
and QC operations," adds Westlake.
Telestream's developments are
based around time-saving not just
for post, but also for those receiving
content. The way to do this, explains
Dove, is to use as much automation as
possible: "With the correct workflow,
in many cases manual QC need only be
done on a master file and output files
may not require any manual QC at all."
The exception to this is to check for
aspects which can currently only be
evaluated during manual QC, such
as lipsync, 'wardrobe malfunctions',
acceptable
language,
pre-9pm
transmission acceptability, he advises.
Interra Systems BATONQC
In the next few years, artificial
intelligence will make significant
inroads into these areas: initially these
tools will be limited in functionality
and value, but they will gradually
replace much of what must now be
done manually. The first of these areas
will be available from Telestream not
at NAB but perhaps by the end of this
year.
combined Mean Opinion Score (MOS),
independent of individual artefact
types. This is part of a greater shift
from QoS to a more complete analysis
of QoE."
Root6 ContentAgent (now under
control of Jigsaw24) provides a
number of AQC checks. A workflow can
be constructed which allows any video,
audio or custom metadata field to be
checked. Decision Nodes can be
added which will automatically
decide the best route through
a workflow for a file based on
asking a number of questions,
such as 'What is the frame
rate?', or 'How many audio
tracks does this file contain?'
For users looking for more
Aurora supports checking for compliance issues
in-depth analysis of files for
Delivery Trends
such items such as PSE, R128 Loudness
Tektronix AQC tool Aurora supports checks and colour levels, ContentAgent
checking for compliance issues integrates with the major proponents
with files against the major delivery of file-based QC products (named
specifications (AS-11 DPP in the as Vidcheck, Baton, Cerify and
UK - itself a subset of the AMWA Digimetrics).
specification, AS-10 PAD in France and
ARD-ZDF in Germany) as well as Netflix Checking HDR
and iTunes.
HDR all starts with filming in the
It identifies three major trends as correct format and follows from
broadly important to facilities and there: material needs to be HDR (10broadcasters for workflows and bits is the minimum, but realistically
QC and these tally with Tektronix 12-bits), wide colour gamut, the right
developments.
colour transform, and in some cases:
"The move to IP for live production provision of data about the display
is a major industry transition," says device used for mastering, maximum
Valentine. "Tektronix is leader in content lightness level (MaxCLL) and
this space with our PRISM platform. maximum average frame light level
Since PRISM is software-defined, we (MaxFALL).
will continue to roll out updates as IP
Some of these parameters can only
standards and specifications continue be calculated when the content is
to evolve."
finished (after editing and grading)
The use of APIs to automate more so the final check for HDR compliance
workflow steps is another major trend, can only be at the end when the file is
driven by the transitions to file-based ready for delivery, as HDR can require
video, software-defined workflows, that this metadata is inserted into
and virtualisation (including cloud- the media file (depending upon the
based computing and storage). "Nearly format).
everything Tektronix offers to our
"The actual implementation and
customers now includes API support generation of HDR content is truly
and we see this support continuing to understood by very few people and
become more robust over time," he there's hardly any HDR content
says.
available right now," says Dove.
"QC tools are adept at finding and
There are a number of reasons.
reporting specific visible HDR requires new concepts to be
and audible artefacts, understood - and some aspects
arising from ingest of these new concepts are
issues, codec or perhaps
counterintuitive,
container
syntax particularly during post. As just
errors, or over- one example: increasing overall
compression of the brightness of a scene may have
source content. zero effect on the scene as the
I n c r e a s i n g l y , display device will limit this.
there is a trend
HDR production is not well
toward more emphasis understood. "The theory is fine' but
on evaluating picture quality as a what are the actual practices that
must be adopted on-set for filming and
viewing rushes?" poses Dove. "Thirdly,
post-production is actually a lot more
complex. It really requires thorough
understanding of colour spaces and
grading and needs different grades for
HDR and SDR.
"Lastly, the tools are just not there
yet. Currently, there's no single postproduction software which can be
used to take camera footage and
produce an HDR compliant output.
This requires the use of at least three
different software packages just to
produce a graded HDR output with
the correct metadata, and the most
commonly-used NLE software does not
provide all the tools required for HDR
media file production."
There is only one professional
monitor feasible for HDR grading and
this costs well over US$30,000; there
are only a few software packages that
will calculate MaxFALL and MaxCLL
(and not the ones that might be
expected).
No HDR Standard
Tektronix agrees that there is some
confusion about the various HDR
standards and how these interact with
the various characteristics of available
cameras. For example, the PQ gamma
curve has been used extensively in
packaged consumer products like Bluray and only works with PQ compatible
displays. HLG (Hybrid Log-gamma) is
used for live production and is Rec.
709 compatible. "HLG can be used with
a standard display but for best results
you'll need a display that supports
HLG," says Valentine.
"Since there are so many HDR
standards what often becomes
critical is the OETF (optical electrical
transfer function) which will ultimately
govern the appearance of the image
on the screen," says Valentine.
"Multiple OETFs have to be managed
in mastering and post-production
for consistency in colour and scene
matching where multiple cameras
have been used in acquisition. This
is an important area of focus for
Tektronix."
Tektronix WFM8300 4K/ UHD
and HDR waveform monitor